1. Field of Invention
The invention relates generally to steering of swimming pool cleaners, and more particularly to the steering of pool cleaners operable with a suction hose attached to a rotatably driven hose coupling.
2. Description of Background Art
Typically, when the contour of a pool surface is such that a portion of the cleaner body is able to contact the pool side walls while another portion of the cleaner is in contact with the pool bottom surface, the cleaner has a likely chance of becoming stuck against the pool surfaces. This is often the case for pool side walls which are generally perpendicular to the pool bottom surface, a "square bottomed" pool. In such circumstances, the drag induced on the cleaner body will over-ride or may substantially impair the cleaner operation and its normal steering operations, causing the cleaner to remain in one position or stay at that position for an inordinate amount of time. Further, the cleaner may be forced to travel parallel to the side wall, or along pool steps. The results are improper pool cleaner operation and an inadequate pool cleaning.
U.S. Pat. No. 4,521,933 describes a random steering device for a submerged suction cleaning head for cleaning swimming pools in which there is a suction hose connecting with the head in a direction generally perpendicular to the surface on which the suction head moves. The steering device operates by intermittently applying torque about the axis of the suction hose where it enters the suction head. The torque is applied by a water motor driven by water flowing from the suction head along the suction hose.
U.S. Patent No. 5,404,607 describing a self-propelled submersible suction cleaner transfers a vibratory movement of an oscillator located within a flow path of a suction chamber for propulsion of the cleaner over a submerged surface of a pool. The oscillator vibratory movement is also converted to a unidirectional rotation of a gear train for rotating the cleaner to improve on the random movement of the cleaner over the pool surface and to maneuver the cleaner away from obstacles such as pool steps which can often stop cleaner movement, as earlier suggested. Flow through the cleaner flow path is caused by connecting the suction chamber to a filter pump and motor by a flexible hose, well known in the art. The hose is connected to a pool cleaner coupling which is rotatably connected to the gear train for rotating the coupling and thus the cleaner about the flexible hose. By its very nature, the flexible hose has rotational play and does not completely transfer the rotational forces applied by the rotating coupling to rotation of the cleaner.
The present invention provides an additional steering mechanism for such pool cleaners by providing a level of steering force from other than the rotating flexible hose.